General Motors this week hit the accelerator on the industry's effort to advance plug-in electric technology.

Plug-in electric technology is seen by proponents as a key step in weaning the country off its dependence on foreign oil by instead pursuing cheaper, cleaner, domestically produced electricity.

"If you look at what's going on in the world with geopolitical unrest and rising global demand for energy, it makes it clear that our dependence on petroleum for transportation presents a lot of risks that will impact GM's business," GM spokesman Brian Corbett said. "GM determined about a year ago as part of the new corporate strategy and our turnaround plan that we wanted to develop vehicles around a diverse fuel strategy."

That diverse strategy includes vehicles that run on ethanol, hydrogen fuel cells, plug-in electricity and traditional gasoline.

"We want to listen to our customers and give them what they want," Corbett said. "To that end, we will offer vehicles with different fuel savings capabilities and at different prices. We don't want to price people out of the market, but we also want to serve people interested in higher fuel-saving technology."

General Motors in November announced plans for its Saturn Vue Greenline Edition Plug-in Hybrid sports utility vehicle, which is more of a traditional hybrid vehicle. The vehicle is to contain both an electric motor and a gasoline engine. The electric battery would work exclusively at speeds below 30 miles an hour and up to a distance of 20 miles. At faster speeds and longer distances, the gasoline engine would work either concurrently or exclusively.

This week, GM introduced a different plug-in model with its Chevrolet Volt concept vehicle. Unlike the Vue and other hybrid systems on the market, the Volt would use only an electric motor for propulsion. The car would be plugged into a regular 110 volt power outlet at night and could travel up to 40 miles on electric power alone. After that point, a gasoline engine would be used to recharge the electric battery.

Even though the company and the industry have shown a sudden enthusiasm over the technology, GM has not set a definitive timeline for when the vehicles will be available commercially. The company is waiting for a more powerful, less expensive battery to be developed.

General Motors is the first automaker officially to endorse the plug-in hybrid concept, but the technology already is commercially available. Some auto shops in California have been installing larger, plug-in batteries in Toyota and Honda hybrids for more than a year. The modifications, however, are not sanctioned by the manufacturers and void most warranties. Toyota and Honda executives have hinted that they are looking into adding a plug-in line to their vehicles. The modifications generally cost several thousand dollars.

Environmentalists, electric utilities and other groups for years have embraced the idea of electric cars, saying the technology is better for the environment and reduces the country's dependence on foreign oil.

Electric motors have virtually no harmful emissions. Plug-in cars, however, are not emission-free, because they use electricity, which is generated mostly from coal and natural gas-fired plants. Even still, power plants generally are considered much less of a pollution problem than vehicle engines.

Many electric utilities also have supported the idea of electric cars because they could help create more stable demand for electricity, said Shane Willbright, executive director of the Municipal Electric Systems of Oklahoma.

"If I'm making better use of my facility, I'm going to have better revenue and won't have to ask customers to improve the revenue stream for me through higher electricity rates," Willbright said. "If they're providing me a revenue stream that normally went for foreign oil, then I would have less need to ask them for assistance when we go tree trimming."

Plug-in electric vehicles generally would draw power at night, when electricity demand is lowest. A large-scale move to plug-in technology would increase electricity usage at a time when power plants generally have excess capacity, he said. At current electricity prices, plug-in costs generally would cost about 65 cents per equivalent gasoline gallon, Willbright said.

Oklahoma Energy Secretary David Fleischaker is a strong supporter of ethanol and other biofuels, but he also has endorsed research into hydrogen fuel cells, electric cars and other alternative fuels.

"The truth of the matter is we're going to need every option available in order to make a serious dent in our reliance on imported fuels used in transportation," Fleischaker said. "I welcome the plug-in technology as a complement to biofuels and other technologies."